A specialized hardware function for performing a particular complex but repetitive task is often controlled by a number of input parameters grouped together called a command. A sequence of commands with differing control parameters may be issued from a controlling processing element. The sequence of commands may operate the specialized hardware to operate tasks repeatedly. For repeating operation, a processing element's command is reissued to the specialized hardware for each repeat operation. The operation may be queued. One type of a queuing structure is known as First-In-First-Out (FIFO) queuing. Another type of queuing structure is a sequential command instruction execution, which allows a sequence of commands to be repeated by restarting the command instruction execution at the beginning of a series of commands stored sequentially in a memory. Each of the above queuing structure has advantages and disadvantages.
For a system having multiple processing elements operating a common specialized hardware, both FIFO and sequential command instruction execution may result in undesirable and/or inefficient operation of the common specialized hardware. FIFO does not automatically reissue the same command or sequence of commands. Accordingly, a processor has to reissue the same command or sequence of commands every time the processor wants to repeat them. One way to implement sequential command instruction execution is to utilize independent instruction sequence execution for each processing element which is costly and does not scale to large numbers of processing element.